Dashboards almost always require fairly high-level information to support the viewer's need for a quick overview. Too much detail, or measures that are expressed too precisely (for example, $3,848,305.93 rather than $3,848,305, or perhaps even $3.8M), just slow viewers down without providing them any benefit. In a way, this problem is the opposite extreme of the one we examined in the previous sectiontoo much information rather than too little.
The dashboard in Figure 3-6 illustrates this type of excess. Examine the two sections that I've enclosed in red rectangles. The lower-right section displays from 4 to 10 decimal digits for each measure, which might be useful in some contexts, but doubtfully in a dashboard. The highlighted section above displays time down to the level of seconds, which also seems like overkill in this context. With a dashboard, every unnecessary piece of information results in time wasted trying to filter out what's important, which is intolerable when time is of the essence.
Figure 3-6. This dashboard shows unnecessary detail, such as times expressed to the second and measures expressed to 10 decimal places.
Clarifying the Vision
Variations in Dashboard Uses and Data
Thirteen Common Mistakes in Dashboard Design
Tapping into the Power of Visual Perception
Eloquence Through Simplicity
Effective Dashboard Display Media
Designing Dashboards for Usability
Putting It All Together